Deformable mirrors are reflectors that can adaptively change their surface curvatures. Usually, these changes can be accomplished in real-time in response to changes in the signal reflected by the surface. One application for deformable mirrors is correcting for aberrations introduced into a signal resulting from transmission through a distorting medium. For example, such mirrors may be used to correct for aberrations introduced into optical signals imaged by an earthbound telescope due to turbulence in the atmosphere above the telescope.
Examples of deformable mirrors are described in U.S. Pat. Nos. 3,904,274 and 4,657,358, which are owned by the assignee of the present invention and the teachings of which are incorporated herein by reference. Basically, these deformable mirrors have face sheets and actuators that connect a back surface of the face sheet to a rigid substrate. The actuators are usually formed from an electrodistortive material that will change its physical characteristics in response to an electrical signal.
The actuators or electrodisplasive transducers are usually made of lead magnesium niobate (PMN) or lead zirconate titanate (PZT). Layers of one of these chemicals are interleaved in a stack with layers of electrical conductors. The arrangement of the electrical conductors permits electrical connections to alternate conductors. Consequently, electrical fields can be established across each layer of the chemical. These electrical fields cause the chemical to either expand or contract. A method for making the electrodisplasive transducers is described in U.S. Pat. No. 4,932,119, which is owned by the assignee of the instant invention and incorporated herein by reference.